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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

ChIPPS: Charged Information-storage Polymer Preparation System

Technological advances are required to support principal science objectives of missions to the solar system’s icy worlds to seek biosignatures of past/extant life. Sensitivity and reliability are key concerns due to small sample sizes (µL – mL) and the extraordinary import of the results. The preparation and processing of small samples can constrain limits of detection (LoDs); therefore, the Charged Information-storage Polymer Preparation System (ChIPPS) project is advancing the technologies of autonomous sample preparation and processing to add a new class of reliably detectable biosignatures: charged polymers and particles, which can be the information storage-and-transmission means for life. Specifically, we are developing an integrated microfluidic sample-processing unit to prepare icy-world samples to support complementary solid-state nanopore-based analyses: 1) charged-polymer analysis, to characterize variations in polymer chain size, shape, and charge vs. position along the chain; 2) polymer and nanoparticle sizing-and-counting, to characterize the relative abundance of polymer chains, as well as small (virus-sized) particles, by their dimensions and charge. Although no such autonomous system presently exists, such measurements can reveal the nature and abundance of charged polymers that could be used by biological systems to store and transfer information—as DNA and RNA are used terrestrially—without limitation to terrestrial nucleic acids, given that life elsewhere may utilize different information store-and-transfer moieties. Key system components include (a) a lysis unit for mechanical sample disruption; b) an ion-exchange column for charged macromolecule/nanoparticle purification; c) dialyzer to remove excess salt; d) concentrator to enhance signal; e) supporting pumps, valves, bubble traps, connectors, filters, etc.; f) interface to nanopore detection instruments.

Space Biology↗
NASA NTRSDate not supplied

In-Situ XRD/XRF to Support Life Detection on Mars

X-ray diffraction / X-ray fluorescence (XRD/XRF) analysis provides the most comprehensive mineralogical / compositional characterization of rocks and soils of any flight-capable technique. XRD data provide quantitative mineralogy (including abundance of X-ray amorphous materials) and crystal chemistry (structure, elemental composition and valence state), and XRF data provide complimentary major, minor, and some trace element abundances. Both types of data are important in evaluating habitability (environment of formation) and biosignature preservation/degradation (post-depositional diagenetic change). Whether or not a relict biosignature is detected, the mineral assemblage and its geochemistry can be used to determine the habitability of an ancient environment (e.g., salinity, pH, temperature), and to identify potential sources of energy for life (e.g., elements in different redox states). In this respect, a null result (a habitable environment lacking evidence of life) can play an important role in constraining the parameters of the search. Conversely, diagenetic alteration (taphonomic change) resulting from post-depositional variations in temperature, pressure or fluid chemistry can preserve evidence of biogenicity, erase such evidence completely or indeed can provide for post-depositional habitable conditions in the subsurface. XRD / XRF data are critical to these determinations. The CheMin instrument on the Mars Science Laboratory (MSL) Curiosity rover is the first XRD instrument flown in space. CheMin operates in transmission geometry with a Co X-ray source to minimize fluorescence from iron. Diffracted photons are collected with an energy-sensitive charge-coupled device (CCD). The position of the diffracted photons provides structural information for minerals, whereas the energy of sample-generated X-ray fluorescence photons provides elemental information, though these XRF data are qualitative. Mineralogical data from the CheMin XRD identified the three circumstances above: habitable depositional environments (e.g., Yellowknife Bay), habitable subsurface/diagenetic environments (e.g., throughout the Murray formation), and diagenetic conditions that may destroy evidence of habitability (e.g., oxidative and acidic environments at Vera Rubin ridge). Technological advances in X-ray technology and lessons learned from the operation of CheMin on Mars have resulted in a next-generation XRD/XRF, called CheMinX. Replacement of CheMin’s CCD with an array of hybrid pixel detectors and improvements in focusing optics dramatically decrease analysis time (15 minutes vs. 22 hours for MSL-CheMin) and result in a better angular resolution (0.18 vs. 0.30 °2θ for MSL-CheMin). This increased resolution improves mineral detection, including discrimination between types of pyroxenes, which is not possible with MSL-CheMin data. The hybrid pixel detectors do not require cooling like the MSL-CheMin CCD, therefore reducing the power needed to operate CheMinX. CheMinX has a silicon-drift detector (SDD) to measure fluoresced photons, enabling the quantification of major, minor, and some trace elements via XRF. XRD/XRF data are collected simultaneously in CheMinX, obviating the need for multiple compositional instruments. The CheMinX design also improves upon MSL-CheMin’s sample handling. Instead of sample cells on wheel, which are often not reusable and add complexity in commanding the instrument, CheMinX has single-use cells in a cartridge/dispenser configuration. Because of these improvements, CheMinX is an ideal instrument for Discovery-class life-detection missions, including Mars Life Explorer that was recommended for development in the Planetary Science and Astrobiology Decadal Survey 2023-2032.

E B Rampe↗
NASA NTRSDate not supplied

Astrobiological Potential of Rocks Acquired By the Perseverance Rover at the Front of the Western Sediment Fan in Jezero Crater, Mars.

Major objectives of the Perseverance rover mission include identifying past habitable environments, collecting rocks that are likely to preserve biosignatures and using the rover’s instruments to look for potential biosignatures in these rocks. The recognition of the > 3.5 billion-year old habitable environments in Jezero crater, Mars (Fig. 1); promised that the mission could achieve these objectives. The western sedimentary fan deposit, the hydrated minerals therein and the carbonate minerals at the margin of this fan were identified as particularly compelling areas in which to search for the signs of past life and collect the oldest aqueously deposited rocks from another planet.

Mars 2020↗
NASA NTRSDate not supplied

Radiation-driven Decomposition of Thiophene and Thiophene-derivatives within H 2 O-ice

Thiophene and several of its derivatives (2-methylthiophene, 3methylthiophene) have been detected on the surface of Mars in lacustrine mudstones using the pyrolysis-GC-MS instrument onboard NASA’s Curiosity Rover. The biosynthesis of thiophenes is considered an important production pathway on Earth, suggesting that thiophenes could serve as a secondary chemical biosignature on Mars. However, Mars lacks a global magnetic field allowing GCRs to readily penetrate the thin CO 2 atmosphere and several meters into the regolith. GCRs can destroy the organic molecules present (i.e., chemical biosignatures). To date, the radiation-driven decomposition of these thiophenes has not been examined and their destruction rates constants have not been measured. Here, we provide radiolytic decomposition rates for thiophene as a neat ice and diluted in water ice to provide additional astrochemical context to the recent detections on Mars.

Patrick D. Tribbett↗
NASA NTRSDate not supplied

Autonomous Science: Simulated Solar System Mission to Enceladus, Icy Ocean Moon of Saturn

Future NASA missions to icy ocean worlds such as Europa, Titan, or Enceladus will collect mass spectrometry (MS) data from exospheres, atmospheres, and plume volatiles to assess their geochemistry and potential for microbial life1. These remote missions face challenges related to limited bandwidth, communication, and power, highlighting the need for science autonomy2 to prioritize data for timely downlink. We extend our previous work on machine learning (ML) biosignature detection from isotope ratio mass spectrometry (IRMS) data to distributed systems missions (DSM) by incorporating the ML and autonomous data quality control and prioritization code into an onboard decision-making platform. We use simulated orbital telemetry for eight orbiters around Enceladus with a mothership to illustrate an automated biosignature and novel seawater chemistry detection with data prioritization from MS analyses of volatile CO2.

Conor Williams↗
NASA NTRS2024

Chapter 9: Life as We Don't Know It

While Earth contains the only known example of life in the universe, it is possible that life elsewhere is fundamentally different from what we are familiar with. There is an increased recognition in the astrobiology community that the search for life should steer away from terran-specific biosignatures to those that are more inclusive to all life-forms. To start exploring the space of possibilities that life could occupy, we can try to dissociate life from the chemistry that composes it on Earth by envisioning how different life elsewhere could be in composition, lifestyle, medium, and form, and by exploring how the general principles that govern living systems on Earth might be found in different forms and environments across the Solar System. Exotic life-forms could exist on Mars or Venus, or icy moons like Europa and Enceladus, or even as a shadow biosphere on Earth. New perspectives on agnostic biosignature detection have also begun to emerge, allowing for a broader and more inclusive approach to seeking exotic life with unknown chemistry that is distinct from life as we know it on Earth.

Asthma↗
DOE OSTI2023

Predicting chronic postsurgical pain: current evidence and a novel program to develop predictive biomarker signatures

Chronic pain affects more than 50 million Americans. Treatments remain inadequate, in large part, because the pathophysiological mechanisms underlying the development of chronic pain remain poorly understood. Pain biomarkers could potentially identify and measure biological pathways and phenotypical expressions that are altered by pain, provide insight into biological treatment targets, and help identify at-risk patients who might benefit from early intervention. Biomarkers are used to diagnose, track, and treat other diseases, but no validated clinical biomarkers exist yet for chronic pain. To address this problem, the National Institutes of Health Common Fund launched the Acute to Chronic Pain Signatures (A2CPS) program to evaluate candidate biomarkers, develop them into biosignatures, and discover novel biomarkers for chronification of pain after surgery. This article discusses candidate biomarkers identified by A2CPS for evaluation, including genomic, proteomic, metabolomic, lipidomic, neuroimaging, psychophysical, psychological, and behavioral measures. Acute to Chronic Pain Signatures will provide the most comprehensive investigation of biomarkers for the transition to chronic postsurgical pain undertaken to date. Data and analytic resources generatedby A2CPS will be shared with the scientific community in hopes that other investigators will extract valuable insights beyond A2CPS’s initial findings. This article will review the identified biomarkers and rationale for including them, the current state of the science on biomarkers of the transition from acute to chronic pain, gaps in the literature, and how A2CPS will address these gaps.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2021

Habitability Models for Astrobiology

Habitability has been generally defined as the capability of an environment to support life. Ecologists have beenusing Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth fromlocal to global scales. Astrobiologists have been proposing different habitability models for some time, with lit-tle integration and consistency among them, being different in function to those used by ecologists. Habitabilitymodels are not only used to determine whether environments are habitable, but they also are used to charac-terize what key factors are responsible for the gradual transition from low to high habitability states. Here wereview and compare some of the different models used by ecologists and astrobiologists and suggest how theycould be integrated into new habitability standards. Such standards will help improve the comparison and charac-terization of potentially habitable environments, prioritize target selections, and study correlations between habit-ability and biosignatures. Habitability models are the foundation of planetary habitability science, and the synergybetween ecologists and astrobiologists is necessary to expand our understanding of the habitability of Earth,the Solar System, and extrasolar planets.

Habitability↗
NASA NTRS2019

The Non-Destructive Separation of Diverse Astrobiologically Relevant Organic Molecules By Customizable Capillary Zone Electrophoresis and Monolithic Capillary Electrochromatography

The in situ detection of organic molecules in space is key to understanding the variety and the distribution of the building blocks of life, and possibly the detection of extraterrestrial life itself. Gas chromatography mass spectrometry (GC-MS) has been the most sensitive analytical instrument for organic analyses in flight, and was used on missions from NASA’s Viking, Phoenix, Curiosity missions to ESA’s Rosetta space probe. While pyrolysis GC-MS revealed the first organics on Mars, this step alters or degrades certain fragile molecules that are excellent biosignatures including polypeptides, oligonucleotides and polysaccharides, rendering the intact precursors undetectable. We have identified a solution tailored to the detection of biopolymers and other biomarkers by the use of liquid-based capillary electrophoresis and electrochromatography. In this study, we show that a capillary electrochromatography (CEC) approach using monolithic stationary phases with tailor-made surface chemistry can separate and identify various polycyclic aromatic hydrocarbons (PAHs), nucleobases and aromatic acids that could be formed under astrophysically relevant conditions. In order to simulate flyby organic sample capture, we conducted hypervelocity impact experiments which consisted of accelerating peptide-soaked montmorillonite particles to a speed of 5.6 km/sec, and capturing them in an amorphous silica aerogel of 10 and 30 mg/cc bulk density. Bulk peptide extraction from aerogel followed by capillary zone electrophoresis led to the detection of only two stereoisomeric peptide peaks. The recovery rates of each step of the extraction procedure after the hypervelocity impact suggest that major peptide loss occurred during the impact. Our study provides initial exploration of feasibility of this approach for capturing intact peptides, and subsequently detecting candidate biomolecules during flight missions that would be missed by GC-MS alone. As the monolith-based electrochromatography technology could be customized to detect specific classes of compounds as well as miniaturized, these results demonstrate the potential of the instrumentation for future astrobiology-related spaceflight missions.

Flyby sample return↗
DOE OSTI2021

Earliest Traces of Life as a Window on Life's Origins

Life is the outcome of a complex network of chemical reactions and mo-lecular interactions that emerged on Earth once primitive chemical automata could self-assemble in such a way that enabled them to self-reproduce and evolve. Yet exactly how, where and when life first appeared on our planet remains unknown. Various lines of evidence from fossilized traces of early life preserved in the geological record provide fundamental, albeit often rudimentary, insight into early life. The oldest fossils record the nature of life more than half a billion years after it emerged on Earth and suggest that considerable metabolic diversity had already evolved by this time. Microfossils, microbial mats, stromatolites and organic and inorganic geochemical signatures have been interpreted as compelling evidence for Archean biodiversity. In spite of the chemical enigmas of the earliest life and its limited record, characterization of the various classes of biosignatures indicative of life in its geological context provides guidance as to the earliest co-evolution of the geosphere and biosphere.

Cavalazzi, Barbara↗
DOE OSTI2021

Accessing the Subsurface Biosphere Within Rocks Undergoing Active Low-Temperature Serpentinization in the Samail Ophiolite (Oman Drilling Project)

The Oman Drilling Project established an “Active Alteration” multi-borehole observatory in peridotites undergoing low-temperature serpentinization in the Samail Ophiolite. The highly serpentinized rocks are in contact with strongly reducing fluids. Distinct hydrological regimes, governed by differences in rock porosity and fracture density, give rise to steep redox (Eh +200 to –750 mV) and pH (pH range 8.5–11.2) gradients within the 300–400 m deep boreholes. The serpentinites and fluids host an active subsurface ecosystem. Microbial cell abundances in serpentinite vary at least six orders of magnitude, from ≤3.5 × 10 1 to 2.9 × 10 7 cells/g. Low levels of biological sulfate reduction (2–1,000 fmol/cm 3 /day) can be detected in rock cores, particularly in rocks in contact with reduced groundwaters with pH < 10.5. Thermodesulfovibrio is the predominant sulfate reducer identified via metagenomic sequencing of adjacent groundwater communities. Here, we infer that transport and reaction of microbially generated sulfide with the serpentine and brucite assemblages gives rise to optical darkening and sulfide overprinting, including the formation of tochilinite-vallerite group minerals, potentially serving as an indicator that this system is inhabited by microbial life. Olivine mesh-cores replaced with ferroan brucite and minor awaruite, abundant veins containing hydroandradite garnet and polyhedral serpentine, and late-stage carbonate veins are suggested as targets for future spatially resolved life-detection investigations. The high-quality whole-round core samples that have been preserved can be further probed to define how life distributes itself and functions within a system where chemical disequilibria are sustained by low-temperature water/rock interaction, and how biosignatures of in situ microbial activity are generated.

58 GEOSCIENCES↗
DOE OSTI2025

Challenges in the detection of gases in exoplanet atmospheres

Claims of detections of gases in exoplanet atmospheres often rely on comparisons between models including and excluding specific chemical species. However, the space of molecular combinations available for model construction is vast and highly degenerate. Only a limited subset of these combinations is typically explored for any given detection. As a result, apparent detections of trace gases risk being artefacts of incomplete modelling rather than robust identification of atmospheric constituents, especially in the low-signal-to-noise regime. Here, using the sub-Neptune K2-18 b as a case study, we show that recent biosignature claims vanish when the model space is expanded, with numerous alternatives providing equally good or better fits. We demonstrate that the significance of a claimed detection relies on the choice of models being compared, and that model preference does not in itself imply the presence of a specific gas. In conclusion, we recommend treating model comparisons instead as relative adequacy tests, which should be supported by theoretical predictions and complementary metrics of statistical significance to attribute a signal to a particular gas.

Astronomy and AstroPhysics↗
DOE OSTI2023

Microbially induced precipitation of silica by anaerobic methane-oxidizing consortia and implications for microbial fossil preservation

Authigenic carbonate minerals can preserve biosignatures of microbial anaerobic oxidation of methane (AOM) in the rock record. It is not currently known whether the microorganisms that mediate sulfate-coupled AOM—often occurring as multicelled consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB)—are preserved as microfossils. Electron microscopy of ANME-SRB consortia in methane seep sediments has shown that these microorganisms can be associated with silicate minerals such as clays [Chen et al., Sci. Rep. 4, 1–9 (2014)], but the biogenicity of these phases, their geochemical composition, and their potential preservation in the rock record is poorly constrained. Long-term laboratory AOM enrichment cultures in sediment-free artificial seawater [Yu et al., Appl. Environ. Microbiol. 88, e02109-21 (2022)] resulted in precipitation of amorphous silicate particles (~200 nm) within clusters of exopolymer-rich AOM consortia from media undersaturated with respect to silica, suggestive of a microbially mediated process. The use of techniques like correlative fluorescence in situ hybridization (FISH), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), and nanoscale secondary ion mass spectrometry (nanoSIMS) on AOM consortia from methane seep authigenic carbonates and sediments further revealed that they are enveloped in a silica-rich phase similar to the mineral phase on ANME-SRB consortia in enrichment cultures. Like in cyanobacteria [Moore et al., Geology 48, 862–866 (2020)], the Si-rich phases on ANME-SRB consortia identified here may enhance their preservation as microfossils. Finally, the morphology of these silica-rich precipitates, consistent with amorphous-type clay-like spheroids formed within organic assemblages, provides an additional mineralogical signature that may assist in the search for structural remnants of microbial consortia in rocks which formed in methane-rich environments from Earth and other planetary bodies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

OrganiCam: a lightweight time-resolved laser-induced luminescence imager and Raman spectrometer for planetary organic material characterization

OrganiCam is a laser-induced luminescence imager and spectrometer designed for standoff organic and biosignature detection on planetary bodies. OrganiCam uses a diffused laser beam (12° cone) to cover a large area at several meters distance and records luminescence on half of its intensified detector. The diffuser can be removed to record Raman and fluorescence spectra from a small spot from 2 m standoff distance. OrganiCam’s small size and light weight makes it ideal for surveying organics on planetary surfaces. Here, we have designed and built a brassboard version of the OrganiCam instrument and performed initial tests of the system.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Nuclear Spectroscopy for the Exploration of Mars and Beyond

Nuclear spectroscopy will continue to play a critical role in planetary exploration in the next decade, including searching for habitable environments and biosignatures, identifying ideal targets for in-situ resource utilization, and continuing its track record in understanding planetary evolution. Nuclear spectroscopy is the only technique that provides bulk geochemical abundance at depth, at a range of spatial scales depending on platform.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

OrganiCam: First Camera for Noncontact Biodetection in Space

Los Alamos National Laboratory designed a compact laser-induced fluorescence imaging camera with Raman spectrometer to identify organic molecules and biosignatures in environments such as Martian caves, icy-moons, and asteroid surfaces. OrganiCam is the primary instrument on the Laser-Induced Fluorescence Exploration of Caves for Organics and Volatiles using an Elevated Platform (LIFE COVE) NASA mission concept. OrganiCam could also determine if instruments being sent into space for NASA are sterile and analyze samples returned to Earth. OrganiCam’s robust design for extreme environments, portability, simple operation, and low power requirement build on LANL’s 50+ years designing robotic instruments for space applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Multi-Site Observational Study to Assess Biomarkers for Susceptibility or Resilience to Chronic Pain: The Acute to Chronic Pain Signatures (A2CPS) Study Protocol

Chronic pain has become a global health problem contributing to years lived with disability and reduced quality of life. Advances in the clinical management of chronic pain have been limited due to incomplete understanding of the multiple risk factors and molecular mechanisms that contribute to the development of chronic pain. The Acute to Chronic Pain Signatures (A2CPS) Program aims to characterize the predictive nature of biomarkers (brain imaging, high-throughput molecular screening techniques, or “omics,” quantitative sensory testing, patient-reported outcome assessments and functional assessments) to identify individuals who will develop chronic pain following surgical intervention. The A2CPS is a multisite observational study investigating biomarkers and collective biosignatures (a combination of several individual biomarkers) that predict susceptibility or resilience to the development of chronic pain following knee arthroplasty and thoracic surgery. This manuscript provides an overview of data collection methods and procedures designed to standardize data collection across multiple clinical sites and institutions. Pain-related biomarkers are evaluated before surgery and up to 3 months after surgery for use as predictors of patient reported outcomes 6 months after surgery. The dataset from this prospective observational study will be available for researchers internal and external to the A2CPS Consortium to advance understanding of the transition from acute to chronic postsurgical pain.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Quantifying the Influence of Jupiter on the Earth’s Orbital Cycles

A wealth of Earth-sized exoplanets will be discovered in the coming years, providing a large pool of candidates from which the targets for the search for life beyond the solar system will be chosen. The target selection process will require the leveraging of all available information in order to maximize the robustness of the target list and make the most productive use of follow-up resources. Here, we present the results of a suite of n-body simulations that demonstrate the degree to which the orbital architecture of the solar system impacts the variability of Earth’s orbital elements. By varying the orbit of Jupiter and keeping the initial orbits of the other planets constant, we demonstrate how subtle changes in solar system architecture could alter the Earth’s orbital evolution—a key factor in the Milankovitch cycles that alter the amount and distribution of solar insolation, thereby driving periodic climate change on our planet. The amplitudes and frequencies of Earth’s modern orbital cycles fall in the middle of the range seen in our runs for all parameters considered—neither unusually fast nor slow, neither large nor small. This finding runs counter to the “Rare Earth” hypothesis, which suggests that conditions on Earth are so unusual that life elsewhere is essentially impossible. Our results highlight how dynamical simulations of newly discovered exoplanetary systems could be used as an additional means to assess the potential targets of biosignature searches, and thereby help focus the search for life to the most promising targets.

79 ASTRONOMY AND ASTROPHYSICS↗